Have "isStrategicBomber" not have any hitpoints
Have the option for "isStrategicBomber" not to have any hitpoints in non strategic bombing combat. It can still be shot down in "AirBattle" and count as a hitpoint then.
And while were at it : ) have "AirBattle" die side be able to be different than their regular combat die side. So it would be kinda like AA. You could have a 12 sided die for "AirBattle" and a six sided for regular combat.